508 
ECONOMIC EELATIONS OF OUR BIRDS. 
to prefer swampy jilaces in the vicinity of ponds. Dr, Cones found it frecjuent- 
ing old buckwheat and corn fields searching for food among the rank weeds. 
Wilson only found it in low thickets. Audubon saw it chasing spiders that run 
nimbly over the water. Mr. Henshaw found it almost always seeking its food 
upon the ground, but on two occasions he saw it feeding in the tops of willows, 
among the fresh pond marshes about Cambridge, Mass. Mr. Jencks has ob¬ 
tained specimens in May which were singing on the lower brandies of a pine 
standing close by a house. 
Food: Spiders and small caterpillars (Samuels). S^iiders (Audubon). 
51. Oporornis FORMOSA (WiLS.), Bd. KENTUCKY WARBLER. Group III. 
Class b. 
A single specimen of this species is reported by Dr. Hoy to have been taken 
near Racine; and Mr. Nelson speaks of it as a very rare summer visitant from 
Southern Illinois. 
Food: Spiders, insects and their larvae (De Kay). It destroys great numbers 
of spiders (Audubon). 
52. Geothlypis trichas (Linn.), Cab. MARYLAND YELLOW-THROAT; 
BLACK-MASKED GROUND WARBLER. Group II. Class a. 
This is a common summer resident in its favoi’ite resorts, and it arrives early 
in May and has departed again by Sejitember 23d. Hazel jiatches, willow clumps, 
berry brush and rank weed tangles, and the borders of woods lieaAuly fringed 
with small bushes, are the surroundings that suit it best, and these are usually 
chosen in damp situations. During the migrations it also visits open fields, or¬ 
chards and gardens. It is a diligent insect-hunter, but we must know more of 
its food, and of the babbits of the insects upon which it feeds, before we can 
know what its real influence is. The dragon-flies, spiders, and hymenopterous 
insects included in the list below suggest that its injurious effects are not slight; 
but we know far too little in regard to the actual service which these insects 
render to enable us to calculate, even approximately, the magnitude of the 
injury. 
Food: Of eight specimens examined, four had eaten, among other insects, eight 
caterpillars; and three, beetles. Among the contents of the stomachs of eleven 
birds, examined collectively, were found twenty-two case-bearing caterpillars 
fColeophora?J; five other larvae — two of them caterpillai-s; six small dragon¬ 
flies; three moths; three dipterous insects; three very small hymenopterous in¬ 
sects; three beetles — among them a squash-beetle; three siiiders; two small 
grasshoppers; one leaf-hopper; two hemipterous insects; and two insect eggs. 
58. Geothlypis Philadelphia (Wils.), Bd. MOURNING WARBLER. 
Group II. Class a. 
This species is introduced in this connection on the evidence of its general dis¬ 
tribution, and on that of Dr. Hoy’s Report. It appears to be an uncommon bird 
everywhere east of the Mississippi in our latitude. Mr. Tripi>e, in giving his 
observations in Minnesota, says of it: “ The Mourning Warbler haunts the edges 
of tamarack swamps and the damp thickets that adjoin them. They are simi¬ 
lar in their habits to the Maryland Yellow-throat, but are not so exclusively de¬ 
voted to thickets and underbrush, frequently ascending the tops of tamaracks, 
for which they show a great predilection.” It obtains the greater part of its 
